With cold weather incoming and energy costs continuing to rise, the efficiency of your windows plays a crucial role in keeping your home comfortable and your bills manageable.

At Futureglaze, we’ve been helping homeowners across Cardiff, Swansea, Newport and beyond tackle window efficiency problems for over three decades, and we often see a familiar question arise: Is repairing my windows worth it?

How do you know if your windows need attention, and more importantly, whether repair or replacement offers better value? This guide will discuss testing your windows’ energy efficiency and help you make an informed decision on repairing or replacing them.

Blue aluminium bay windows

DIY Window Efficiency Tests

Before calling in professionals, there are several simple tests you can do yourself to check how well your windows are performing.

Visual Inspection

Start by examining all parts of the window carefully:

Look for gaps between the window frame and the wall
Check for damaged seals or weatherstripping
Inspect glass panes for cracks, even small ones
See if there’s condensation between panes of double glazing
Check if the window closes and locks properly

Even minor issues can lead to significant heat loss. Damaged seals or small gaps allow warm air to escape and cold air to enter, forcing your central heating to work harder and increasing your carbon footprint.

The Candle Test

This simple test can help identify air leakage:

Close all doors and windows
Light a candle and slowly move it around the edges of your windows
If the flame flickers or the smoke drifts sideways, you’ve found a draught

Thermal Check

On a cold day:

Run your hand around the window frame and glass
Feel for cold spots or noticeable temperature differences
Pay special attention to corners and where the glass meets the frame

Cold spots indicate heat transfer and energy loss. With efficient windows, the inside of the window should feel close to room temperature even if it’s cold outside.

Monitor Your Energy Bills

Have your energy bills increased more than expected? While many factors affect energy use, windows typically account for around 25-30% of a home’s heat loss. If you’ve noticed your bills climbing despite no change in your habits, inefficient windows could be the culprit.

Compare your current bills to previous years, adjusting for any price increases from your provider. A steady increase in consumption might indicate declining window performance.

Professional Energy Audits

While DIY tests give you a good starting point, professional assessments provide more detailed information about your windows’ energy efficiency.

A professional window assessment might include:

Thermal imaging cameras that precisely locate heat loss
Blower door tests that measure overall air leakage
U-value measurements that quantify heat transfer through materials
Comprehensive inspections of all window components

Repair or Replace: Making the Right Choice

Once you’ve identified efficiency issues, the next question is whether to repair or replace. Here’s what to consider:

When Repair Makes Sense

Repairs are often worth it when:

The window frames are in good condition
The inefficiency comes from specific, fixable issues like failed seals or damaged hardware
Your windows are relatively modern but have developed minor problems
You’re working with a limited budget
You have special or period windows that would be expensive to replace

For windows less than a decade old, repairs can often restore much of their original efficiency at a fraction of replacement costs.

When Replacement Offers Better Value

New windows might be the better option when:

Your existing windows are very old with multiple issues
The frames are warped, rotted or structurally compromised
You have single glazing and want the benefits of double or triple glazing
The type of glass in your current windows is outdated
You’re looking for significant improvements in energy rating and long-term energy savings

Modern windows with high quality glazing offer much better insulation than older models. If your current windows are significantly underperforming, the initial investment in replacement can pay for itself through lower bills and a more comfortable living environment.

Timber effect windows in showroom

Futureglaze Window Repair Service

At Futureglaze, we take pride in being able to repair windows that other companies might write off. Our experienced team deals with all the everyday issues that affect window performance:

Replacing misted or failed double-glazed units while keeping the existing frame
Fixing broken seals and worn gaskets that cause draughts
Repairing faulty mechanisms that prevent windows from closing properly
Adjusting uPVC or aluminium systems for a better fit
Replacing damaged weatherstripping
Resolving condensation problems
Repairing or replacing handles, hinges, and locking systems

Our repair service is designed to be straightforward and cost-effective. We don’t believe in replacing what can be fixed, and we’ll always give you honest advice about whether repair is the right option for your situation.

For many South Wales homes, our repairs have restored window efficiency and function, extending window lifespan by years and delivering excellent value compared to full replacement.

Futureglaze Energy Efficient Windows

When repair isn’t the best option, we offer a comprehensive range of energy efficient windows:

Our uPVC windows achieve A-ratings for energy efficiency with U-values as low as 0.8 W/m²K
Our aluminium windows feature advanced thermal breaks to prevent heat transfer
All our window styles, from casement to sliding sash, are designed with energy performance in mind

Don’t Put Up with Inefficient Windows

Testing your windows’ energy efficiency is the first step toward a warmer home and lower utility bills. Whether the solution is a targeted repair or full replacement depends on your specific situation, the condition of your existing windows, and your long-term goals for your home.

At Futureglaze, we’re committed to helping South Wales homeowners find the right solution for their needs and budget. We won’t recommend replacement when a repair will do, and we’ll always provide clear information so you can make an informed decision.

If you’re concerned about your windows’ performance, we invite you to contact us for a no obligation assessment. Our team can help you understand your options and the potential energy savings each might deliver.

For more information, you can:

Frequently Asked Questions

What is the easiest DIY way to check if my windows are draughty?

The candle test is quick and simple – move a lit candle around the window edges. If the flame flickers, you’ve likely found an air leak.

Can repairing my windows really make a significant difference to their energy efficiency?

Yes, in many cases. Simple repairs like replacing failed seals, fixing locks so windows close properly, or replacing weatherstripping can dramatically reduce draughts and heat loss.

How can I tell if my windows need repair or full replacement for better energy efficiency?

Consider the overall condition and age of your windows. If they’re structurally sound but have specific issues, repair is often worthwhile. If they’re very old, have multiple problems, or are single-glazed when the rest of your home is well-insulated, replacement might offer better long-term value.

Window Energy Efficiency Test: Is Repair Worth It?